Add org.osgi.framework.system.packages to config.ini of samples so that we can specify javax.transaction mandatory properties

With recent updates we are now loading some transaction classes from the system bundle and others from the transaction spec bundle. This is causing a linkage error as follows:

java.lang.LinkageError: loader constraint violation: when resolving interface method "javax.transaction.Transaction.enlistResource(Ljavax/transaction/xa/XAResource;)Z" the class loader (instance of org/eclipse/osgi/internal/baseadaptor/DefaultClassLoader) of the current class, org/apache/aries/transaction/jdbc/ConnectionWrapper, and the class loader (instance of org/eclipse/osgi/internal/baseadaptor/DefaultClassLoader) for resolved class, javax/transaction/Transaction, have different Class objects for the type javax/transaction/xa/XAResource used in the signature
at org.apache.aries.transaction.jdbc.ConnectionWrapper.<init>(ConnectionWrapper.java:67)

To avoid the error we need to add org.osgi.framework.system.packages entries that include a mandatory attribute on the transaction packages so that our bundles do not wire to the system bundle which only includes a subset of the necessary classes.